1. Field of the Invention
This invention relates to securing devices for plumbing pipes and more precisely to strapping devices which both secure the pipe to a surface while maintaining a separation between the pipe and the mounting surface.
2. Description of the Prior Art
It has long been known in the plumbing industry that water pipes strapped against wooden studs and joists of buildings can create annoying noises which may be transferred into adjacent rooms. These noise problems are often so loud and obnoxious to the occupant that a repairman or plumber must be called to locate and resolve the problem. The exact location of the problem is quiet difficult to find and is usually not in an area which is readily accessible to repair once found.
One specific cause of noisy plumbing is the vibration or "hammering" of the pipes against the wood created by the flow of fluid and the shutting and opening of valves. This vibration problem only occurs while water is running and is caused by an insufficient number of straps or insufficient tightness of the strapping. The problem is avoidable with straps currently available on the market if they are installed correctly.
A second cause of noisy plumbing is the natural contraction and expansion of the pipes attributable to varying extremes of temperatures of the water. This unavoidable expansion and contraction of the pipes causes both the diameter and the length of the pipes to vary. It is the changing length of the piping which has been found to be a primary cause of noise problems. As the lengths of the pipes change with expansion and contraction, the pipes slide longitudinally through the pipe strap and against the wood to which the plumbing is strapped. The sliding of the plumbing against the wooden members can create a variety of noises ranging from sounding like a violin to a trombone or worse. Since the wooden framing members are normally supporting the ceiling or a wall of a building oppositely the side of the strapped plumbing, the sound of the sliding pipe is carried into the room through the wood.
The majority of pipe straps in use today are manufactured of steel due to the strength and rigidity of the metal. A large portion of plumbing pipes in the 1/2" to 1" diameter range used today are manufactured of a copper alloy which unfortunately reacts with the steel in the straps causing electrolysis between the two dissimilar metals. Modern plumbing installation procedures under such conditions employ some form of dielectric insulation between the pipe and metal strap to prevent electrolysis. Pipe straps and hangers which make this procedure simple and fast are currently commercially available on the market. There are however, several drawbacks to the available straps with regard to sound control.
One principal drawback is that some types of straps use insulation material which is provided as a separate unit from the strap. This is less convenient and more time consuming to install than a strap which comes complete with the insulating medium inherent to the device. Another drawback is that other straps use only a thin ring of insulating material over the metal which works well to separate the strap from the pipe, but does not separate the pipe from the wood framing member.
A past art patent search was conducted to examine dielectrically insulated pipe straps which also have means for maintaining a separation between the pipe and the mounting surface. Of the devices examined, the following appeared most pertinent to my invention:
A patent issued to E. J. Carson on July 28, 1942, U.S. Pat. No. 2,291,148, teaches a pipe hanger. The Carson pipe hanger uses a U-shaped metal hanger with a narrow ring of permanently attached insulation covering the metal at the closed end of the "U". In use, the Carson device would allow abutment of the pipe against the surface of the wooden stud due to the positioning of the insulation.
A patent issued to S. Delserro on May 8, 1979, U.S. Pat. No. 4,153,228, teaches a self-tightening clamp which requires attachment to the wood with separate nails or screws. The Delserro clamp requires the installer to locate appropriately sized nails or screws and then keep them within reach when applying the clamps to the pipe. This is generally inconvenient and adds time to the installation process. The Delserro device also appears that if the clamp was sufficiently flexible to be spread allowing installation of the clamp anywhere along a length of pipe his clamp would be inadequately rigid to prohibit vibrating or "hammering" noises since it attaches at only one location. If the Delserro clamp must be inserted over the end of the pipe, the installation of any significant length of pipe would prove to be an extremely tedious and time consuming job.